---
title: INCR
description: The Redis INCR command is used to increment the numeric value stored in a key by one.
sidebar:
  order: 3
---

import { Code } from '@astrojs/starlight/components'

Increment the numeric value stored in key by one.

If the key does not exist, the key's value will first be initialized to 0, and then the INCR operation will be performed.

If the value contains the wrong type, or the string value cannot be represented as a number, an error is returned.

The value of this operation is limited to 64-bit signed number representation.

### Redis Native Command Syntax

<Code code={`INCR key`} lang="bash" />

**Parameter Description**

- **key**: The key to increment

### Detailed Explanation

The INCR command is an atomic operation and can be used to implement counter functionality. It is an operation for string type, but requires the string to be parseable as an integer.

## Redisun Usage

In redisun, the INCR command is implemented through the IncrCommand class and the incr method in the Redisun class.

### Basic Usage

<Code code={`Redisun redisun = Redisun.create(options -> {
    options.setAddress("redis://127.0.0.1:6379");
});

// Increment the key's value
long result = redisun.incr("mycounter");
System.out.println("Counter value: " + result);

// Asynchronous version
CompletableFuture<Long> future = redisun.asyncIncr("mycounter");
future.thenAccept(value -> System.out.println("Async counter value: " + value));`} lang="java" />

## Notes

1. If the key does not exist, it will be automatically created and initialized to 0
2. If the key exists but is not a numeric string, an exception will be thrown
3. The value range is limited to 64-bit signed integer range
4. The operation is atomic and suitable for concurrent scenarios

## References

- [Redis INCR Command Official Documentation](https://redis.io/commands/incr/)